Typically, with display devices such as televisions, and optical elements such as camera lenses, in order to reduce surface reflections and increase transmitted light, an anti-reflection treatment is performed on the light-incident surface. For example, one proposal for such an anti-reflection treatment is to laminate, onto the light-incident surface, an optical body on which is formed a micro concave-convex structure in which the average cycle of the concavities and convexities is less than or equal to the visible light wavelengths (such as a moth-eye structure, for example).
At the surface having such a micro concave-convex structure, a refractive index changes gradually with respect to incident light, and thus a steep change in refractive index, which causes reflection, does not occur. Accordingly, forming such a micro concave-convex structure on the light incident surface prevents reflection of incident light for a wide wavelength region.
Regarding the method of forming a micro concave-convex structure at the nanometer scale, for example, Patent Literature 1 discloses a method of performing dry etching by using island-shaped nanoparticles as a protective mask. Also, Patent Literature 2 and 3 disclose methods of using the anodic oxidation of an aluminum film to form a micro concave-convex structure having multiple sub-micrometer concavities in the aluminum film. Furthermore, Patent Literature 4 discloses a method of using electron-beam lithography to form a micro concave-convex structure in which the average cycle of the concavities and convexities is less than or equal to a certain wavelength.
In addition, Patent Literature 1 and 2 also disclose that it is possible to form a transfer product to which the micro concave-convex structure has been transferred by pressing a structure on which has been formed such a micro concave-convex structure into a resin or the like.
Note that regarding a method of treating a structure on which has been formed the micro concave-convex structure as a mold to form a transfer product to which the micro concave-convex structure has been transferred, for example, the technology disclosed in Patent Literature 5 below is also known. Specifically, Patent Literature 5 discloses that by pressing a roll-shaped mold, on the outer circumferential surface of which a fine pattern has been formed, into a film or the like while also rotating the mold, it is possible to transfer the fine pattern onto a film of large surface area.
Also, in recent years, even higher optical characteristics are being demanded of optical bodies. From such a perspective, with Patent Literature 2 to 4, the anti-reflection function described above as well as an anti-glare function are conferred to an optical body. Specifically, with Patent Literature 2, there is prepared an aluminum film on the surface of which are distributed coarse crystal particles, and then anodic oxidation and etching are repeatedly performed on the aluminum film. With this arrangement, an aluminum film in which a micro concave-convex structure is superimposed onto the rough surface of the aluminum film is produced. Additionally, with Patent Literature 3 and 4, the surface of a substrate is roughened by a mechanical or chemical method, and a micro concave-convex structure is superimposed onto the rough surface. According to these technologies, an anti-glare function is realized by the rough surface formed on the substrate, while an anti-reflection function is realized by the micro concave-convex structure superimposed onto the rough surface.